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  • C++ find multiple keys from a std::multimap

    - by sch0ck9
    I have a STL::multimap and I search to populate a std::list with value which key is duplicated. Can I find/insert to a std::list the value of elements for all key where count 1 without counting them one by one? std::multimap<int, std::string> mm ; mm[0] = "a" ; mm[1] = "b" ; mm[0] = "c" ; mm[2] = "j" ; mm[2] = "k" ; std::list<std::string> lst ; lst might contains "a" ,"c","j","k" ; I try this template <class K, class V> class extract_value { private: K last_key_ ; std::list<V> m_list_value ; std::pair<K, V> first_elem ; public: extract_value(const K& k_): last_key_(k_) { } void operator() (std::pair<const K, V> elem) { if (last_key_ == elem.first) { m_list_value.push_back(elem.second) ; } else { // First entry last_key_ = elem.first; first_elem= elem ; } } std::list<V> get_value() { return m_list_value ; } }; ex_ = for_each(mm.begin(),mm.end(), extract_value<int, std::string>(0)) ; std::list<std::string> lst = ex_.get_value() ; I'm not sure that this code compile.

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  • Encrypt string with public key only

    - by vlahovic
    i'm currently working on a android project where i need to encrypt a string using 128 bit AES, padding PKCS7 and CBC. I don't want to use any salt for this. I've tried loads of different variations including PBEKey but i can't come up with working code. This is what i currently have: String plainText = "24124124123"; String pwd = "BobsPublicPassword"; byte[] key = pwd.getBytes(); key = cutArray(key, 16); byte[] input = plainText.getBytes(); byte[] output = null; SecretKeySpec keySpec = null; keySpec = new SecretKeySpec(key, "AES"); Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding"); cipher.init(Cipher.ENCRYPT_MODE, keySpec); output = cipher.doFinal(input); private static byte[] cutArray(byte[] arr, int length){ byte[] resultArr = new byte[length]; for(int i = 0; i < length; i++ ){ resultArr[i] = arr[i]; } return resultArr; } Any help appreciated //Vlahovic

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  • LINQ to Entity: using Contains in the "select" portion throws unexpected error

    - by Chu
    I've got a LINQ query going against an Entity Framework object. Here's a summary of the query: //a list of my allies List<int> allianceMembers = new List<int>() { 1,5,10 }; //query for fleets in my area, including any allies (and mark them as such) var fleets = from af in FleetSource select new Fleet { fleetID = af.fleetID, fleetName = af.fleetName, isAllied = (allianceMembers.Contains(af.userID) ? true : false) }; Basically, what I'm doing is getting a set of fleets. The allianceMembers list contains INTs of all users who are allied with me. I want to set isAllied = true if the fleet's owner is part of that list, and false otherwise. When I do this, I am seeing an exception: "LINQ to Entities does not recognize the method 'Boolean Contains(Int32)' method" I can understand getting this error if I had used the contains in the where portion of the query, but why would I get it in the select? By this point I would assume the query would have executed and returned the results. This little ditty of code does nothing to constrain my data at all. Any tips on how else I can accomplish what I need to with setting the isAllied flag? Thanks

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  • Problem with UITextView

    - by user367039
    I have a strange problem with trying to pass a string from one viewcontroller to another view controller if the string originates from a UITextview instead of UITextfield. Both UITextview.text and UITextfield.text are of type NSString. The following code takes either Textfield.text or Textview.text depending on the fieldType and puts it into a string called aString. NSString *aString = [[NSString alloc] init]; if (fieldType == 3) { aString = textView.text; } else { aString = textField.text; } When I examine aString on either cases, I can see that it has successfully assigned the text into aString. I then pass the string to the other view controller using this code. [delegate updateSite:aString :editedFieldKey :fieldType]; [self.navigationController popViewControllerAnimated:YES]; This works fine if aString originated from textfield.text but nothing happens except the view controller is popped if aString was from textview.text This is the code that takes aString and does stuff with it, however it doesn't even execute the first line of code "NSLog(@"Returned object: %@, field type:%@", aString,editedFieldKey);" if aString was from textview.text Any help will be appreciated. -(void)updateSite:(NSString *)aString :(NSString *)editedFieldKey :(int)fieldType { NSLog(@"Returned object: %@, field type:%@", aString,editedFieldKey); switch (fieldType) { case 0: //string [aDiveSite setValue:aString forKey:editedFieldKey] ; NSLog(@"String set %@",[aDiveSite valueForKey:editedFieldKey] ); break; case 1: //int [aDiveSite setValue:[NSNumber numberWithInt:aString.intValue] forKey:editedFieldKey]; NSLog(@"Integer set"); break; case 2: //float NSLog(@"Saving floating value"); [aDiveSite setValue:[NSNumber numberWithFloat:aString.floatValue] forKey:editedFieldKey]; NSLog(@"Float set"); break; case 3: //Text view [aDiveSite setValue:aString forKey:editedFieldKey]; NSLog(@"Textview text saved"); default: break; } [self.tableView reloadData]; }

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  • Overloading generic implicit conversions

    - by raichoo
    Hi I'm having a little scala (version 2.8.0RC1) problem with implicit conversions. Whenever importing more than one implicit conversion the first one gets shadowed. Here is the code where the problem shows up: // containers class Maybe[T] case class Nothing[T]() extends Maybe[T] case class Just[T](value: T) extends Maybe[T] case class Value[T](value: T) trait Monad[C[_]] { def >>=[A, B](a: C[A], f: A => C[B]): C[B] def pure[A](a: A): C[A] } // implicit converter trait Extender[C[_]] { class Wrapper[A](c: C[A]) { def >>=[B](f: A => C[B])(implicit m: Monad[C]): C[B] = { m >>= (c, f) } def >>[B](b: C[B])(implicit m: Monad[C]): C[B] = { m >>= (c, { (x: A) => b } ) } } implicit def extendToMonad[A](c: C[A]) = new Wrapper[A](c) } // instance maybe object maybemonad extends Extender[Maybe] { implicit object MaybeMonad extends Monad[Maybe] { override def >>=[A, B](a: Maybe[A], f: A => Maybe[B]): Maybe[B] = { a match { case Just(x) => f(x) case Nothing() => Nothing() } } override def pure[A](a: A): Maybe[A] = Just(a) } } // instance value object identitymonad extends Extender[Value] { implicit object IdentityMonad extends Monad[Value] { override def >>=[A, B](a: Value[A], f: A => Value[B]): Value[B] = { a match { case Value(x) => f(x) } } override def pure[A](a: A): Value[A] = Value(a) } } import maybemonad._ //import identitymonad._ object Main { def main(args: Array[String]): Unit = { println(Just(1) >>= { (x: Int) => MaybeMonad.pure(x) }) } } When uncommenting the second import statement everything goes wrong since the first "extendToMonad" is shadowed. However, this one works: object Main { implicit def foo(a: Int) = new { def foobar(): Unit = { println("Foobar") } } implicit def foo(a: String) = new { def foobar(): Unit = { println(a) } } def main(args: Array[String]): Unit = { 1 foobar() "bla" foobar() } } So, where is the catch? What am I missing? Regards, raichoo

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  • Counting combinations in c or in python

    - by Dennis
    Hello I looked a bit on this topic here but I found nothing that could help me. I need a program in Python or in C that will give me all possible combinations of a and b that will meet the requirement n=2*a+b, for n from 0 to 10. a, b and n are integers. For example if n=0 both a and b must be 0. For n=1 a must be zero and b must be 1, for n=2 a can be 1 and b=0, or a=0 and b=2, etc. I'm not that good with programming. I made this: #include <stdio.h> int main(void){ int a,b,n; for(n = 0; n <= 10; n++){ for(a = 0; a <= 10; a++){ for(b = 0; b <= 10; b++) if(n == 2*a + b) printf("(%d, %d), ", (a,b)); } printf("\n"); } } But it keeps getting strange results like this: (0, -1079628000), (1, -1079628000), (2, -1079628000), (0, -1079628000), (3, -1079628000), (1, -1079628000), (4, -1079628000), (2, -1079628000), (0, -1079628000), (5, -1079628000), (3, -1079628000), (1, -1079628000), (6, -1079628000), (4, -1079628000), (2, -1079628000), (0, -1079628000), (7, -1079628000), (5, -1079628000), (3, -1079628000), (1, -1079628000), (8, -1079628000), (6, -1079628000), (4, -1079628000), (2, -1079628000), (0, -1079628000), (9, -1079628000), (7, -1079628000), (5, -1079628000), (3, -1079628000), (1, -1079628000), (10, -1079628000), (8, -1079628000), (6, -1079628000), (4, -1079628000), (2, -1079628000), (0, -1079628000), ideone Any idea what is wrong? Also if I could do this for Python it would be even cooler. :D

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  • Quicksort / vector / partition issue

    - by xxx
    Hi, I have an issue with the following code : class quicksort { private: void _sort(double_it begin, double_it end) { if ( begin == end ) { return ; } double_it it = partition(begin, end, bind2nd(less<double>(), *begin)) ; iter_swap(begin, it-1); _sort(begin, it-1); _sort(it, end); } public: quicksort (){} void operator()(vector<double> & data) { double_it begin = data.begin(); double_it end = data.end() ; _sort(begin, end); } }; However, this won't work for too large a number of elements (it works with 10 000 elements, but not with 100 000). Example code : int main() { vector<double>v ; for(int i = n-1; i >= 0 ; --i) v.push_back(rand()); quicksort f; f(v); return 0; } Doesn't the STL partition function works for such sizes ? Or am I missing something ? Many thanks for your help.

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  • File streaming in PHP - How to replicate this C#.net code in PHP?

    - by openid_kenja
    I'm writing an interface to a web service where we need to upload configuration files. The documentation only provides a sample in C#.net which I am not familiar with. I'm trying to implement this in PHP. Can someone familiar with both languages point me in the right direction? I can figure out all the basics, but I'm trying to figure out suitable PHP replacements for the FileStream, ReadBytes, and UploadDataFile functions. I believe that the RecService object contains the URL for the web service. Thanks for your help! private void UploadFiles() { clientAlias = “<yourClientAlias>”; string filePath = “<pathToYourDataFiles>”; string[] fileList = {"Config.txt", "ProductDetails.txt", "BrandNames.txt", "CategoryNames.txt", "ProductsSoldOut.txt", "Sales.txt"}; RecommendClient RecService = new RecommendClient(); for (int i = 0; i < fileList.Length; i++) { bool lastFile = (i == fileList.Length - 1); //start generator after last file try { string fileName = filePath + fileList[i]; if (!File.Exists(fileName)) continue; // file not found } // set up a file stream and binary reader for the selected file and convert to byte array FileStream fStream = new FileStream(fileName, FileMode.Open, FileAccess.Read); BinaryReader br = new BinaryReader(fStream); byte[] data = br.ReadBytes((int)numBytes); br.Close(); // pass byte array to the web service string result = RecService.UploadDataFile(clientAlias, fileList[i], data, lastFile); fStream.Close(); fStream.Dispose(); } catch (Exception ex) { // log an error message } } }

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  • Bind a ViewModel to a DropDownListFor with a third value besides dataValueField/dataTextField

    - by Elisa
    When I show a list of testplanViewModels in my View and the user selects one the SelectedTestplanId is returned to the Controller post action. What should also be returned is the TemplateId which belongs to the SelectedTestplanId. When the AutoMapper definition is run the Testplan.TestplanId is implicitly copied over to the TestplanViewModel.TestplanId. The same could be done by providing a TemplateId on the TestplanViewModel. When the user selects now a "TestplanViewModel" in the View, how can I attach the TemplateId to the controller action to access it there? The DropDownList does not allow 2 dataValueFields! CreateMap<Testplan, TestplanViewModel>().ForMember(dest => dest.Name, opt => opt.MapFrom(src => string.Format("{0}-{1}-{2}-{3}", src.Release.Name, src.Template.Name, src.CreatedAt, src.CreatedBy))); public ActionResult OpenTestplanViewModels() { IEnumerable<Testplan> testplans = _testplanDataProvider.GetTestplans(); var viewModel = new OpenTestplanViewModel { DisplayList = Mapper.Map<IEnumerable<Testplan>, IEnumerable<TestplanViewModel>>(testplans) }; return PartialView(viewModel); } public class TestplanViewModel { public int TestplanId { get; set; } public string Name { get; set; } } public class OpenTestplanViewModel { [Required(ErrorMessage = "No item selected.")] public int SelectedTestplanId { get; set; } public IEnumerable<TestplanViewModel> DisplayList { get; set; } } OpenTestplanViewModel @using (Html.BeginForm("Open", "Testplan")) { @Html.ValidationSummary(false) @Html.DropDownListFor(x => x.SelectedTestplanId, new SelectList(Model.DisplayList, "TestplanId", "Name"), new { @class = "listviewmodel" }) }

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  • Regarding some Update Stored procedure

    - by Serenity
    I have two Tables as follows:- Table1:- ------------------------------------- PageID|Content|TitleID(FK)|LanguageID ------------------------------------- 1 |abc |101 |1 2 |xyz |102 |1 -------------------------------------- Table2:- ------------------------- TitleID|Title |LanguageID ------------------------- 101 |Title1|1 102 |Title2|1 ------------------------ I don't want to add duplicates in my Table1(Content Table). Like..there can be no two Pages with the same Title. What check do I need to add in my Insert/Update Stored Procedure ? How do I make sure duplicates are never added. I have tried as follows:- CREATE PROC InsertUpdatePageContent ( @PageID int, @Content nvarchar(2000), @TitleID int ) AS BEGIN IF(@PageID=-1) BEGIN IF(NOT EXISTS(SELECT TitleID FROM Table1 WHERE LANGUAGEID=@LANGUAGEID)) BEGIN INSERT INTO Table1(Content,TitleID) VALUES(@Content,@TitleID) END END ELSE BEGIN IF(NOT EXISTS(SELECT TitleID FROM Table1 WHERE LANGUAGEID=@LANGUAGEID)) BEGIN UPDATE Table1 SET Content=@Content,TitleID=@TitleID WHERE PAGEID=@PAGEID END END END Now what is happening is that it is inserting new records alright and won't allow duplicates to be added but when I update its giving me problem. On my aspx Page I have a drop down list control that is bound to DataSource that returns Table 2(Title Table) and I have a text box in which user types Page's content to be stored. When I update, like lets say I have a row in my Table 1 as shown above with PageID=1. Now when I am updating this row, like I didn't change the Title from the drop down and only changed Content in the text box, its not updating the record ..and when Stored procedure's Update Query does not execute it displays a Label that says "Page with this title exists already." So whenever I am updating an existing record that label is displayed on screen.How do I change that IF condition in my Update Stored procedure?? EDIT:- @gbn :: Will that IF condition work in case of update? I mean lets say I am updating the Page with TitleID=1, I changed its content, then when I update, it's gonna execute that IF condition and it still won't update coz TitleID=1 already exits!It will only update if TitleID=1 is not there in Table1. Isn't it? Guess I am getting confused. Please answer.Thanks.

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  • Get more error information from unhandled error

    - by Andrew Simpson
    I am using C# in a desktop application. I am calling a DLL written in C that I do not have the source code for. Whenever I call this DLL I get an untrapped error which I trap in an UnhandledException event/delegate. The error is : object reference not set to an instance of an object But the stack trace is empty. When I Googled this the info back was that the error was being hanlded eleswhere and then rethrown. But this can only be in the DLL I do not have the source code for. So, is there anyway I can get more info about this error? This is my code... in program.cs... AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e) { try { Exception _ex = (Exception)e.ExceptionObject; //the stact trace property is empty here.. } finally { Application.Exit(); } } My DLL... [DllImport("AutoSearchDevice.dll", EntryPoint = "Start", ExactSpelling = false, CallingConvention = CallingConvention.StdCall)] public static extern int Start(int ASD_HANDLE); An I call it like so: public static void AutoSearchStart() { try { Start(m_pASD); } catch (Exception ex) { } }

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  • escape sequence in c

    - by prp
    int main() { char *arr="\\0\1\8234\0"; int i=0; while(arr[i]) { switch(arr[i]) { case '0': printf("is no"); break; case '00': printf("is debugging\n"); break; case 0: printf("It is Avishkar\n"); break; case '\\': printf("This "); break; case '\1': printf("t s"); break; case '8': printf("o s"); break; case '2': printf("imp"); break; case '3': printf("le as"); break; case 2: case 3: case 4: case 8: printf("This "); break; default: printf(" it seems\n"); break;} i++; } } please explain the o/p ? i am not able to get it..

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  • How to display panels with component in frame

    - by terence6
    Why my JFrame 'frame' is diplaying empty window, when it should give me 3 menu buttons and my own painted JComponent below ? What am I missing here ? import java.awt.*; import javax.swing.*; public class Eyes extends JFrame { public static void main(String[] args) { final JFrame frame = new JFrame("Eyes"); frame.setPreferredSize(new Dimension(450, 300)); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel players = new JPanel(new GridLayout(1, 3)); players.add(new JButton("Eyes color")); players.add(new JButton("Eye pupil")); players.add(new JButton("Background color")); JPanel eyes = new JPanel(); eyes.add(new MyComponent()); JPanel content = new JPanel(); content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS)); content.add(players); content.add(eyes); frame.getContentPane(); frame.pack(); frame.setVisible(true); } } class MyComponent extends JComponent { public MyComponent(){ } @Override public void paint(Graphics g) { int height = 120; int width = 120; Graphics2D g2d = (Graphics2D) g; g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); BasicStroke bs = new BasicStroke(3.0f); g2d.setStroke(bs); g2d.setColor(Color.yellow); g2d.fillOval(200, 200, height, width); g2d.setColor(Color.black); g2d.drawOval(60, 60, height, width); } }

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  • Strange results from OdbcDataReader reading Sqlite DB

    - by stout
    This method returns some strange results, and was wondering if someone could explain why this is happening, and possibly a solution to get my desired results. Results: FileName = what I'd expect FileSize = what I'd expect Buffer = all bytes = 0 BytesRead = 0 BlobString = string of binary data FieldType = BLOB (what I'd expect) ColumnType = System.String Furthermore, if the file is greater than a few KB, the reader throws an exception stating the StringBuilder capacity argument must be greater than zero (presummably because the size is greater than Int32.MaxValue). I guess my question is how does one properly read large BLOBs from an OdbcDataReader? public static String SaveBinaryFile(String Key) { try { Connect(); OdbcCommand Command = new OdbcCommand("SELECT [_filename_],[_filesize_],[_content_] FROM [_sys_content] WHERE [_key_] = '" + Key + "';", Connection); OdbcDataReader Reader = Command.ExecuteReader(CommandBehavior.SequentialAccess); if (Reader.HasRows == false) return null; String FileName = Reader.GetString(0); int FileSize = int.Parse(Reader.GetString(1)); byte[] Buffer = new byte[FileSize]; long BytesRead = Reader.GetBytes(2, 0, Buffer, 0, FileSize); String BlobString = (String)Reader["_content_"]; String FieldType = Reader.GetDataTypeName(2); Type ColumnType = Reader.GetFieldType(2); return null; } catch (Exception ex) { Tools.ErrorHandler.Catch(ex); return null; } }

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  • Animate and form rows, arrays, AS3

    - by VideoDnd
    Question How can I animate and form rows together? Explanation One 'for loop' is for animation, the other 'for loop' is for making rows. I want to understand how to use arrays and create a row of sprite animations. 'for loop' for animation //FRAMES ARRAY //THIS SETS UP MY ANIMATION FOR TIMER EVENT var frames:Array = [ new Frame1(), new Frame2(), new Frame3(), new Frame4(), new Frame5(), new Frame6(), new Frame7(), new Frame8(), new Frame9(), new Frame0(), ]; for each (var frame:Sprite in frames) { addChild(frame); } 'for loop' for rows //THIS MAKES A ROW OF DISPLAY OBJECTS var numberOfClips:Number = 11; var xStart:Number = 0; var yStart:Number = 0; var xVal:Number = xStart; var xOffset:Number = 2; for (var $:Number=0; $<numberOfClips; $++) { //DUDE ARRAY var dude:Array = frames; dude.y = yStart +11; dude.x = xVal +55; xVal = dude.x + dude.width + this.xOffset; } timer var timer:Timer = new Timer(100); timer.addEventListener(TimerEvent.TIMER, countdown); function countdown(event:TimerEvent) { var currentFrame:int = timer.currentCount % frames.length; for (var i:int = 0; i < frames.length; ++i) { frames[i].visible = (i == currentFrame); } } timer.start(); counter experiment My new class I'm working on loops through 10 different display objects that are numbers. For those following, I'm trying to make something like NumbersView.

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  • What is the minimal licensable source code?

    - by Hernán Eche
    Let's suppose I want to "protect" this code about being used without attribution, patenting it, or through any open source licence... #include<stdio.h> int main (void) { int version=2; printf("\r\n.Hello world, ver:(%d).", version); return 0; } It's a little obvious or just a language definition example.. When a source stop being "trivial, banal, commonplace, obvious", and start to be something that you may claim "rights"? Perhaps it depends on who read it, something that could be great geniality for someone that have never programmed, could be just obvious for an expert. It's easy when watching two sources there are 10000 same lines of code, that's a theft.. but that's not always so obvious. How to measure amount of "ownness", it's about creativity? line numbers? complexity? I can't imagine objetive answers for that, only some patches. For example perhaps the complexity, It's not fair to replace "years of engeneering" with "copy and paste". But is there any objetive index for objetive determination of this subject? (In a funny way I imagine this criterion: If the licence is longer than the code, then there is no owner, just to punish not caring storage space and world resources =P)

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  • Problems breaking out of nested loops

    - by user1040281
    I have problems breaking out off these nested loops correctly. What the code is trying to do is to indicate that a customer has rented a certain movie. Both the movie and customer are compared to properties of arraylist objects and then if all checks out the name property and ID property of a movie object are added as a string to another arraylist. All this works correctly as long as I use the first movie (from movies) and the first customer (from customers) but if I try renting other movies further down my arraylist with other customers then it adds the rented movie to the customerRentedMovies arraylist but prints out the "else message". I figure I need to break out of the foreach(blabla) loops aswell? or could goto be used? Comments was removed (looked kinda messy, can explain further if needed) public void RentMovie(string titel, int movieID, string name, int customerID) { foreach (Customer customer in customers) { if (name == customer.Name && customerID == customer.CustomerID) { foreach (MovieInfo movie in movies) { if (titel == movie.Titel && movieID == movie.MovieID) { movie.rented = true; string rentedMovie = string.Format("{0} ID: {1}", movie.Titel, movie.MovieID); customer.customerRentedMovies.Add(rentedMovie); break; } else { Console.WriteLine("No movie with that titel and ID!"); } } break; } else { Console.WriteLine("No customer with that ID and name"); } } }

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  • C# - Bug in Code Logic

    - by Matthew
    I have some code which keeps track of the number of times a button has been clicked. As a matter of fact, when the page first loads, a counter is set to 0. On every postback, the counter is incremented by 1. I have only one button on the page. The main idea behind this is to allow the user to enter some details 4 times. If he enters invalid details for 4 times, he is redirected to an error page. Otherwise, he is redirected to a confirmation page. This is my code: if (!this.IsPostBack) { Session["Count"] = 0; } else { if (Session["Count"] == null) { Session.Abandon(); Response.Redirect("CheckOutErrorPage.htm"); } else { int count = (int)Session["Count"]; if (count == 3) { Session.Abandon(); Response.Redirect("CheckOutFailure.aspx"); } else { count++; Session["Count"] = count; } } } Everything works as it should except that if the user enter invalid details for 3 times and then he enters VALID details on the 4th time, the user is redirected to the Error Page (because he has tried 4 times) instead of the confirmation page. How can I solve this please?

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  • Question about Virtual Inheritance hierarchy

    - by Summer_More_More_Tea
    Hi there: I encounter this problem when tackling with virtual inheritance. I remember that in a non-virtual inheritance hierarchy, object of sub-class hold an object of its direct super-class. What about virtual inheritance? In this situation, does object of sub-class hold an object of its super-class directly or just hold a pointer pointing to an object of its super-class? By the way, why the output of the following code is: sizeof(A): 8 sizeof(B): 20 sizeof(C): 20 sizeof(C): 36 Code: #include <iostream> using namespace std; class A{ char k[ 3 ]; public: virtual void a(){}; }; class B : public virtual A{ char j[ 3 ]; public: virtual void b(){}; }; class C : public virtual B{ char i[ 3 ]; public: virtual void c(){}; }; class D : public B, public C{ char h[ 3 ]; public: virtual void d(){}; }; int main( int argc, char *argv[] ){ cout << "sizeof(A): " << sizeof( A ) << endl; cout << "sizeof(B): " << sizeof( B ) << endl; cout << "sizeof(C): " << sizeof( C ) << endl; cout << "sizeof(D): " << sizeof( D ) << endl; return 0; } Thanks in advance. Kind regards.

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  • Building static (but complicated) lookup table using templates.

    - by MarkD
    I am currently in the process of optimizing a numerical analysis code. Within the code, there is a 200x150 element lookup table (currently a static std::vector < std::vector < double ) that is constructed at the beginning of every run. The construction of the lookup table is actually quite complex- the values in the lookup table are constructed using an iterative secant method on a complicated set of equations. Currently, for a simulation, the construction of the lookup table is 20% of the run time (run times are on the order of 25 second, lookup table construction takes 5 seconds). While 5-seconds might not seem to be a lot, when running our MC simulations, where we are running 50k+ simulations, it suddenly becomes a big chunk of time. Along with some other ideas, one thing that has been floated- can we construct this lookup table using templates at compile time? The table itself never changes. Hard-coding a large array isn't a maintainable solution (the equations that go into generating the table are constantly being tweaked), but it seems that if the table can be generated at compile time, it would give us the best of both worlds (easily maintainable, no overhead during runtime). So, I propose the following (much simplified) scenario. Lets say you wanted to generate a static array (use whatever container suits you best- 2D c array, vector of vectors, etc..) at compile time. You have a function defined- double f(int row, int col); where the return value is the entry in the table, row is the lookup table row, and col is the lookup table column. Is it possible to generate this static array at compile time using templates, and how?

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  • Newbie: Render RGB to GTK widget -- howto?

    - by Billy Pilgrim
    Hi All, Big picture: I want to render an RGB image via GTK on a linux box. I'm a frustrated GTK newbie, so please forgive me. I assume that I should create a Drawable_area in which to render the image -- correct? Do I then have to create a graphics context attached to that area? How? my simple app (which doesn't even address the rgb issue yet is this: int main(int argc, char** argv) { GdkGC * gc = NULL; GtkWidget * window = NULL; GtkDrawingArea * dpage = NULL; GtkWidget * page = NULL; gtk_init( &argc, & argv ); window = gtk_window_new( GTK_WINDOW_TOPLEVEL ); page = gtk_drawing_area_new( ); dpage = GTK_DRAWING_AREA( page ); gtk_widget_set_size_request( page, PAGE_WIDTH, PAGE_HEIGHT ); gc = gdk_gc_new( GTK_DRAWABLE( dpage ) ); gtk_widget_show( window ); gtk_main(); return (EXIT_SUCCESS); } my dpage is apparently not a 'drawable' (though it is a drawing area). I am confused as to a) how do I get/create the graphics context which is required in subsequent function calls? b) am I close to a solution, or am I so completely *#&@& wrong that there is no hope c) a baby steps tutorial. (I started with hello world as my base, so I got that far). any and all help appreciated. bp

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  • For loop index out of range ArgumentOutOfRangeException when multithreading

    - by Lirik
    I'm getting some strange behavior... when I iterate over the dummyText List in the ThreadTest method I get an index out of range exception (ArgumentOutOfRangeException), but if I remove the threads and I just print out the text, then everything works fine. This is my main method: public static Object sync = new Object(); static void Main(string[] args) { ThreadTest(); Console.WriteLine("Press any key to continue."); Console.ReadKey(); } This method throws the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Thread t = new Thread(() => PrintThreadName(dummyText[i])); // <-- Index out of range?!? t.Name = ("Thread " + (i)); t.IsBackground = true; t.Start(); } } private static void PrintThreadName(String text) { Random rand = new Random(DateTime.Now.Millisecond); while (true) { lock (sync) { Console.WriteLine(Thread.CurrentThread.Name + " running " + text); Thread.Sleep(1000+rand.Next(0,2000)); } } } This does not throw the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Console.WriteLine(dummyText[i]); // <-- No exception here } } Does anybody know why this is happening?

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  • Nullable<T> as a parameter

    - by ferch
    I alredy have this: public static object GetDBValue(object ObjectEvaluated) { if (ObjectEvaluated == null) return DBNull.Value; else return ObjectEvaluated; } used like: List<SqlParameter> Params = new List<SqlParameter>(); Params.Add(new SqlParameter("@EntityType", GetDBValue(EntityType))); Now i wanted to keep the same interface but extend that to use it with nullable public static object GetDBValue(int? ObjectEvaluated) { if (ObjectEvaluated.HasValue) return ObjectEvaluated.Value; else return DBNull.Value; } public static object GetDBValue(DateTime? ObjectEvaluated) {...} but i want only 1 function GetDBValue for nullables. How do I do that and keep the call as is is? Is that possible at all? I can make it work like: public static object GetDBValue<T>(Nullable<T> ObjectEvaluated) where T : struct { if (ObjectEvaluated.HasValue) return ObjectEvaluated.Value; else return DBNull.Value; } But the call changes to: Params.Add(new SqlParameter("@EntityID ", GetDBValue<int>(EntityID)));

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  • Insert Stored Procedure does not Create Database Record

    - by SidC
    Hello All, I have the following stored procedure: ALTER PROCEDURE Pro_members_Insert @id int outPut, @LoginName nvarchar(50), @Password nvarchar(15), @FirstName nvarchar(100), @LastName nvarchar(100), @signupDate smalldatetime, @Company nvarchar(100), @Phone nvarchar(50), @Email nvarchar(150), @Address nvarchar(255), @PostalCode nvarchar(10), @State_Province nvarchar(100), @City nvarchar(50), @countryCode nvarchar(4), @active bit, @activationCode nvarchar(50) AS declare @usName as varchar(50) set @usName='' select @usName=isnull(LoginName,'') from members where LoginName=@LoginName if @usName <> '' begin set @ID=-3 RAISERROR('User Already exist.', 16, 1) return end set @usName='' select @usName=isnull(email,'') from members where Email=@Email if @usName <> '' begin set @ID=-4 RAISERROR('Email Already exist.', 16, 1) return end declare @MemID as int select @memID=isnull(max(ID),0)+1 from members INSERT INTO members ( id, LoginName, Password, FirstName, LastName, signupDate, Company, Phone, Email, Address, PostalCode, State_Province, City, countryCode, active,activationCode) VALUES ( @Memid, @LoginName, @Password, @FirstName, @LastName, @signupDate, @Company, @Phone, @Email, @Address, @PostalCode, @State_Province, @City, @countryCode, @active,@activationCode) if @@error <> 0 set @ID=-1 else set @id=@memID Note that I've "inherited" this sproc and the database. I am trying to insert a new record from my signup.aspx page. My SQLDataSource is as follows: <asp:SqlDataSource runat="server" ID="dsAddMember" ConnectionString="rmsdbuser" InsertCommandType="StoredProcedure" InsertCommand="Pro_members_Insert" ProviderName="System.Data.SqlClient"> The click handler for btnSave is as follows: Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click Try dsAddMember.DataBind() Catch ex As Exception End Try End Sub When I run this page, signup.aspx, provide required fields and click submit, the page simply reloads and the database table does not reflect the newly-inserted record. Questions: 1. How do I catch the error messages that might be returned from the sproc? 2. Please advise how to change signup.aspx so that the insert occurs. Thanks, Sid

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  • How to partition bits in a bit array with less than linear time

    - by SiLent SoNG
    This is an interview question I faced recently. Given an array of 1 and 0, find a way to partition the bits in place so that 0's are grouped together, and 1's are grouped together. It does not matter whether 1's are ahead of 0's or 0's are ahead of 1's. An example input is 101010101, and output is either 111110000 or 000011111. Solve the problem in less than linear time. Make the problem simpler. The input is an integer array, with each element either 1 or 0. Output is the same integer array with integers partitioned well. To me, this is an easy question if it can be solved in O(N). My approach is to use two pointers, starting from both ends of the array. Increases and decreases each pointer; if it does not point to the correct integer, swap the two. int * start = array; int * end = array + length - 1; while (start < end) { // Assume 0 always at the end if (*end == 0) { --end; continue; } // Assume 1 always at the beginning if (*start == 1) { ++start; continue; } swap(*start, *end); } However, the interview insists there is a sub-linear solution. This makes me thinking hard but still not get an answer. Can anyone help on this interview question?

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